package StringExercise;
//String toUpperCase():将字符串中英文转换为大写
//String toLowerCase():将字符串中英文转换为小写
public class ToUpperCaseDemo1 {
    public static void main(String[] args) {
        String str1="我爱Java";
        String upper1=str1.toUpperCase();
        System.out.println(upper1);
        String lower1=str1.toLowerCase();
        System.out.println(lower1);

        String str2="ABCabcDDDddd";
        String upper2=str2.toUpperCase();
        System.out.println(upper2);
        String lower2=str2.toLowerCase();
        System.out.println(lower2);

    }
}
